I have the 3.1 v6 - during in-town driving the heat guage goes to the first of the 3 red lines and stays there until I get on the highway and then it's 210-220 - WEIRDLY; if I turn on the AC or heat, my car cool to 220 immediatly. Makes no sense! AC would make it run hotter right?! I read all about the 160 deg thermostat in the thermo thread and today. I was going to go with the 160 origianlly. I changed my mind and went with a 195 thermo and it did the same thing. No change. The radiador has been flushed recently (10k ago) - I've only had the car a short time and no matter what I do it overheats in town. It runs fine, and the needle NEVER buries into the red, just hovers over that first red line. any ideas?

 

Your fan isn't turning on when it needs to be then. When you turn on the AC the fan automatically kicks in, thus cooling it down. You probably have a problem with the sensor that is supposed to trigger the fan to kick on at a certain temp

 

oh... well that makes sense. lol - so does anyone have a part number for that or maybe is there a performance upgrade switch that will turn it on sooner? btw - would really rather not do a manual switch.

 

Jet part # 60600 fan switch will turn your fan on at 195 and off at 180-185. Summit Racing stocks the part as does Jegs and some auto parts stores. It`s an easy install.

 

Thank you very much! THIS FORUM RULES!!!!

 

I finally got around to fixing this. Ordered my fan switch... got it... turns out the 92 RS doesn't have a fan switch, it's ECM controled... so what should I be looking to replace now?

 

you didnt notice a difference when you put in the 195 stat because thats the stock spec. Go get a 180 stat for sure if you want to stop over heating and a 195 stat wont work with that fan switch your buying anyway, cos itll turn on when the fan does. get a 180 stat, you dont need a 160.

 

my car doesn't have a brass fanswitch, it's a 92. So I'm stuck with a fanswitch I can't use. Also, I have already decided on the 180 thermo but thanks Is there a relay or something? Anyone have this problem?

 

Ohio, If you got your fan switch from Summit or Jegs you can return it. If you don`t have a fan switch, you will probably have to re-program your ECM or replace the chip. I`m not up on computers so maybe someone else who knows these things can give you a price and instructions on how to do it. The cheapest thing you can do is install a manual fan switch. It`s easy to do and works, the down side is if you forget to turn it on. If you need the wiring diagrams let me know and pm me your e-mail address. I installed manual fan switches in my `88 Iroc and they work great, no complaints. I also hooked up an LED on each relay so I know when my fan/fans are on.

 

ebay and Tbichips.com can probably help u on the chip....a quick fix until u get ahold of the problem..

 

My car does the same thing, I had it flushed and it still did it, so i changed the thermostat to a 180 and it continued to do it, my fan turns on but i guess it isnt soon enough.

If your interested in selling the switch you got let me know.

How hard are these to take out? reinstall?

 

I can let it go for 20 - I got it for 50 on ebay brand new from nook and tranny. Plus shipping ofcourse - where do you live? Do you need pics? Are you certain your car is equiped with a brass pressure switch on the BACK of the passenger head? Install I would imagine would be hard as ***** - you probly need to attack it from under the car.

 

I would think the temperature sensor for the ECM is faulty.
It's similar to the temp guage sensor but is on a separate circuit.
Don't know the part # for it though.

 

To install a manual switch that only works when the car is on, all you nee dis 1 wire and a switch. If interested, let me know and I will elaborate.

 

I don't know about the manual fan switch thing, I think I want it to be stock configuration. Temp sensor? Could this be it?

http://www.autozone.com/selectedZip,.../selectZip.htm

There is a switch that looks like this on my car - red and all easy to get to right near the coal box.

 

The way I wired mine the computer still controls the fan, so you dont need to worry about forgettng the switch, but you can turn it on if need be.

 

Naah, that red thing says it's a switch, even a pressure switch, and by the looks of it it could be just that. Idk. If it's there you could just try to short it out and see what happens, but I'm more inclined to believe it's the SU109 Coolant Temperature Sensor: http://www.autozone.com/R,APP226363/...ductDetail.htm
But I don't know if this is for the guage or for the ECM, or if they are same. Try to look for these on the engine, pull their plugs and see if it affects the guage or the way the engine runs, maybe it sets the Check Engine Light. If it does the former then keep looking, if it does the latter (two) then it's your suspect. Then you might try to short out the contact, I believe that should make the ECM think it's real hot and turn on the fan.

 

That's actually the first thing I replaced! lol - according to the thread on here about the jet fan switch you should always replace the coolant temp sensor under the TB - As a by and by, there is a coolant temp SWITCH for the guage that goes behind the air conditioner compressor and has a single green wire running to it. I had to order the switch I linked you guys to, it won't be here for 3 days but I'll let you know if it works. What worries me the
most is that the fan does come on without the AC, but only after the guage is well in the red. And let me tell you, the heat coming off that engine and the crappy way it runs when it gets that hot; It's definatly NOT a faulty guage. So, can a switch be half broken and decide to work once the car is over-heating? OR is it just one of those things where it's broke or it's not? Here's hoping the little red peice of plastic fixes it. lol

 

Hehe, sometimes shops don't know a switch from a linear sensor.. A guage needs a sensor while an idiot light and a direct fan control uses a switch. The ECM also needs a sensor, as it adjusts the fueling and timing etc. based on temperature, and it also turns on the fan based the temp it sees. Obviously your guage sensor is ok, but since the car also runs crappy when hot it seems that the ECM temp sensor is out of spec's. Both a switch and a sensor may fail both catastrophically or by a shift in the temperature response.
Good luck, we'll be waiting for the verdict..

 

If you choose to install a manual switch, you don't have to make any changes that effect the ecm turning on your fan. By nature the ecm only completes ground circuits. If the ecm was ever wired to the hot side of a load, it would burn out because it cannot handle more than a few milliamps. Your ecm should make the ground on your fan relay to turn on the fan. Your a/c is wired in series to make the same ground when you turn on the a/c. All you have to do is run a wire parrallel with the ground wire on the fan relay to a switch inside the car, and then run a wire from the other side of the switch to the body to make a ground. If you forget to turn the switch on, you will get overheating if the ecm doen't turn it on. If you forget to turn it off, you might discover your engine not running warm enough and have to turn it off to warm the engine.

 

thats what I was talking about! it works very well.

 

Well, when my part comes in I'll throw it on there. IF it's no dice I'll be inquiring more about the switch. Thanks guys! - Nate

 

My car did the exact same thing. To save a ton of money I found the wire under the dash that controlled the fan and connected it to a switch. Now every time I drive I have control of when I want the fan on. It actually backkfired once and I left the fan on and my battery died but still.......
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I did the exact same thing